Screw jack



De. 23, 1930. G H JAME 1,786,305

SCREW JACK Filed Jan. 2'7, 192; 2 Sheets-Sheet l IN VEN TOR.

ATTORNEY Dec. 23, I930. G. H. JAMES 1,786,305

SCREW JACK Filed Jan 27, 1927 x 2 Sheets-Sheet 2 Patented Dec. 23, 1930UNITED STATES J AT OFF tor.

GEORGE H. JAMES, or OAKLAND, CALIFORNIA, nssreivonor ONE-HALF r Farina.1e; SIMPSON, or OAKLAND, oanrronnrn SCREW JACK Application filed January27, 1927; Serial No. 163,860.

This invention relates to improvements in screw-jacks and moreparticularly to quickacting screw-jacks adapted for "use in jacking upautomobiles or like heavy objects.

Y My invention contemplates the use'of an" elevating screw somewhatsimilar to that commonly used in ordinary screw-jack con struction,except that the screw is horizontally disposed and preferably providedwith right and left-hand threaded shanks, hearing correspondinglythreaded spaced nut members having toggle members of oppositedisposition, to which are secured a supporting base and elevating head,the said nut mem- 5 bers being adapted, upon the rotation of the screw,to travel toward or away from each objects resting close to the floor orother sur- 235 face, wherein the limited space is too small for theordinary screw-jack.

The principal object of the invention is the provision of a screw-jackthat h2LSCQI1S1dQF- able range of vertical movement andthat 39 when inits retracted position may be inserted into small spaces or under.objects resting very close to any working surface, the floor or groundlevel.

Another object of the invention is the pro- 35 vision of a screw-jackthat is exceptionally compact, quick-acting, powerful, of very simpleconstruction, and that combines in its construction ahorizontally-disposed elevating screw.

A further object of the invention is the provision of a screw-jack ofthe class indicated, that has a conveniently arranged actuating handledesigned for ease of manipulation and to which manual power maybe read-13 ily and advantageously applied.

Other objects and advantages of my invention will be more clearlybrought out with reference to the accompanying-two sheets of drawingsand subjoined specificat1on,- in

which:

such as be apparent from] the foregoing,"

" Figure 1 is a side elevation illustrating the preferred embodiment ofmy inventon, and in which the device is shown in its limiting elevatedposition; v

Fig. 2 is an end elevation with the elevating screw shown in section,the view being indicated by the line22 of Fig. 1;

Fig. 3 is a side elevation analogous to Fig. 1, except that it shows thejack in its retracted or lowermost position;

Fig. 4 is an enlarged detail view illustrating the central portion ofthe elevating screw and which is provided with a centrally disposedspacing section forming stops to limit. the lnward movement of the nutmembers; the screw is shown provided withright and left-hand threadedsections;

Fig. 5 is a side elevation embodying a modified structure of theinvention and in which a single-threaded elevating screw is. used; thisform is provided with but one nut memberand one extremity of theelevating screw is swivelled in a bearing member as shown; Fig. 6 is anend elevation with the elevatmg screw shown in cross section, the viewbeing indicated by the line G-6 of 5;

Fig. 7 is a side elevation showing the eel: in its lowermost position;and

F ig.-8 is an enlarged sectional detail sliow= mg the elevating screwand its outer bearing member.

Referringto the drawing with great particularity, the numeral 10designates a rectangular-shaped base plate having upstand- 111g flanges11 and '11 integrally formed thereon, and sufficiently spaced apart toaccommodate a pair of spaced links 12 and 12 hingedly secured at theirlower ends to the plate 10 by means of bolts 13 and 13 which are held inplace by cotter pins 14, the whole forming a toggle member 15:

The elevatlng screw 16 consists of a spindle 17 and 17 of course pitchprovided with a centrally-disposed spacin'gmember 18,, end

' having right and left-hand threaded sections stop-collars 20 and 20',andouter squared ex- 7 trcmities 21*and 21" for thereception of a socketwrench'22,

Theelevating screw sections 17 and 1'? are provided with a pair ofcorrespondingly threaded nut members 23 and '23 which travel back andforth as the screw is rotated. The said nut members are provided withlower sets of cars 24, 2d and upper sets of ears 26 and 26,respectively; the lower sets are hingedly connected to the upper ends ofthe links 12 and 12 by the bolts 27 and 27, and the upper sets 26 and 26are connected to the upper pair of links 28 and 28 by the bolts 29 and29.

The upper extremities ot the links 28 and 28, are hinged to the headplate 30 which is provided with flanges 31 and 31, between which theupper links extend and to which they are secured by the bolts 32 and 32,the whole forming a, toggle member 33 similar to the lower toggle member15.

The spacing member 18 is provided with stop flanges 3d and 3 forlimiting the inward movement of the nut members 2?, and 23 travel of thehead 30; and the elevatingscrew collars 20 and 20 limit the outwardmovement of said nut members and deter- .mine the lowermost limit ofmovement of said head, and further prevent the lower links from passingbeyond theirdead centers when in the position shown in Fig. 3.

The elevating-screw sections 17 and 1? are provided with a suitableheavy thread having a steep pitch as shown in detail in Figure at, thepitch of these threads deter mining the speed with which the head 30 iselevated by ordinary manipulation of the socket wrench 22.

It will be apparent with reference to the modification shown in Figures5 to 8 inclusive, that the elevating screw 16 may be provided with asingle right-hand thread 1'4" and a nut member 23 threaded in a mannersimilar to the nut member 23, while the member corresponding to the nutmember 23 is held in the swivel bearing formed on the inner end of thescrew. The bearing consists of a flange 36 and stop shoulder 36 and acollar 37 held in place by a pin 38, and as thus constituted allows thefree rotation of the screw relative thereto. An arrangement of thischaracter functions in a manner similar to the form shown in Figures 1to 4 inclusive, except that the one screw and nut do the work of the twoin the former; the rest of the construction is considerably less andsuch ajack has a greater range of vertical movement.

It is obvious from the foregoing that I have produced a screw-jack whichis exceedingly simple in construction and operation, and that by theutilization of the horizontal screw arrangement, permits of the jacksinsertion into much smaller spaces than the ordinary jack having avertically-arranged screw, and furthermore, a jack constructed inaccordance with the principles of my inand determining the uppermostlimit of.

vention, is decidedly quicker in action than the ordinary screw-jack inuniversal use.

hat I claim as new and desire to secure by Letters Patent of the UnitedStates, is the following 1. In a screw-jaek of the class described, anelevating screw having right and lefthand threaded sections,correspondingly threaded nut members carried by said screw sections, abase for engagement with a fixed object, a head for engagement with arelatively movable object, toggle members of equal length pivotallyconnecting said nut members with said head, and toggle members of equallength pivotally COUHKCHHW said nut members with said base, said ltoggle members being shorter than said first toggle members.

2. In a screw-jack oi the class described. an elevating screw havingright and letthand threaded sections separated by an integral collarsection, correspond?ugly threaded nut members carried by said threadedscrew sections and cngageable with said collar section as a stopthere-toiwhen said screw-jack is fully ext-ended, a base tor engagementwith a fixed object, a head for engagement with a relatively movable objct, a pair of toggle members of like hi connecting said nut members withsaid head, a second pair of toggle members of l ke length connectingsaid nut members with said base, the toggle members of one pair thereofbeing shorter than those of the otlu pair whereby the toggle members ofthe shorter pair will define a larger angle than that defined by thetoggle members of the other pair when the screw-jack is contracted, andstop means on said screw operative against said nuts to limit themaximum angle definable by the toggle members of the shorter pair to avalue less than and approxi mating one hundred eighty degrees.

In testimony whereof, I afiix my signature.

GEORGE H. JAMES.

iii?

